LONDON, Dec 10 (Reuters) - Up to 100,000 Britons suffering from cancer and rare diseases are to have their genetic codes fully sequenced and mapped as part of government efforts to boost drug development and improve treatment.

Britain will be the first country to introduce a database of genetic sequences into a mainstream health service, officials say, giving doctors a more advanced understanding of a patient’s illness and what drugs and other treatments they need.

It could significantly reduce the number of premature deaths from cancer within a generation, Prime Minister David Cameron’s office said in a statement.

“By unlocking the power of DNA data, the NHS (National Health Service) will lead the global race for better tests, better drugs and above all better care,” Cameron said on Monday.

His government has set aside 100 million pounds ($160 million) for the project in the taxpayer-funded NHS over the next three to five years.

Harpal Kumar, chief executive of the charity Cancer Research UK, said the work would uncover new information from which doctors and scientists will learn about the biology of cancers and develop new ways to prevent, diagnose and treat them.

He said some targeted, or personalised, cancer treatments such as Novartis’ Gleevec, or imatinib - a drug for chronic myeloid leukaemia - are already helping to treat patients more effectively.

Some critics of the project, known as the “UK genome plan”, have voiced concerns about how the data will be used and shared with third parties, including with commercial organisations such as drug companies.

Genewatch, a campaign group fighting for genetic science and technologies to be used in the public interest, has said anyone with access to the database could use the genetic codes to identify and track every individual on it and their relatives.

Cameron’s office said the genome sequencing would be entirely voluntary and patients would be able to opt out without affecting their NHS care. It said the data would be made anonymous before it is stored.